Answer this question truthfully
### Question: What causes Oppositional defiant disorder?
### Response: This disorder is more common in boys than in girls.
Some studies have shown that it affects 20% of school-age children. However, most experts believe this figure is high due to changing definitions of normal childhood behavior, and possible racial, cultural, and gender biases.
This behavior typically starts by age 8, but it may start as early as the preschool years.
This disorder is thought to be caused by a combination of biological, psychological, and social factors.